Electric control motor

Abstract

In control motors having an armature rotatable counter to a spiral spring, a problem arises that the set force of the spiral spring can be changed by the process of installation. The disclosed control motor is intended to enable setting of the force of the spiral spring after installation. To enable setting of the force of the spiral spring after installation, relative to which an armature of a control motor is rotatable, a shaft on which the armature is supported is screwed with a screw end into a threaded bore of a housing bottom end. Connected to the shaft is an adjusting element, which with a driver arm engages an end portion provided on the outer end of the spiral spring. By rotating the ends of the shaft, which are accessible from outside, the force of the spiral spring can be changed. The invention is preferably applicable to idling adjusters, but it is not limited to this field of application.

What is claimed and desired to be secured by Letters Patent of the United States is: 
     
       1. An electric control motor, in particular for controlling a throttle cross section in a line carrying a fluid to an internal combustion engine, having an armature (17) rotatable in a housing (22), a spiral spring (32) connected by an inner end to said armature which rotates said armature in said housing counter to the force of said spiral spring, said spiral spring including an outer end (53) which is secured on an adjusting element (58), said adjusting element is located such that it is variable independently of a rest position of said armature (17), in order to set a force of the spiral spring (32) on said armature, said adjusting element (58) is rotatably supported coaxially with said armature (17) and includes a driver arm (57) which engages said outer end (53) of said spiral spring (32), said housing (22) includes a threaded bore (43) into which an outer screw end (44) of an armature shaft (19) is threaded, and said adjusting element (58) is firmly connected to said shaft about which said armature (17) is rotatably supported. 
     
     
       2. A control motor as defined by claim 1, which includes means for fixing said shaft (19) in said housing (22) after a rotation thereof for setting a force of the spiral spring (32) for rotation of said armature. 
     
     
       3. An electric control motor, in particular for controlling a throttle cross section in a line carrying a fluid to an internal combustion engine, having an armature (17) rotatable in a housing (22), a spiral spring (32) connected by an inner end to said armature which rotates said armature in said housing counter to the force of said spiral spring, said spiral spring including an outer end (53) which is secured on an adjusting element (58), said adjusting element is located such that it is variable independently of a rest position of said armature (17), in order to set a force of the spiral spring (32) on said armature, said adjusting element (58) is rotatably supported coaxially with said armature (17) and includes a driver arm (57), which engages said outer end (53) of said spiral spring (32), said adjusting element (58) includes a cylinder step (65) which protrudes into a slide fit bore (47) of a cap (49) of the housing (22) and is rotatably supported therein. 
     
     
       4. A control motor as defined by claim 3, in which said adjusting element (58) is fixable in said housing (22) after a rotation thereof for setting a force of said spiral spring (32) on said armature. 
     
     
       5. A control motor as defined by claim 3, in which said armature (17) is rotatably supported on said shaft (19), and an end (46) of said shaft (19) protrudes into a bearing bore (70) in said cylinder step (65) of the adjusting element (58).